


Osamu: the cooler twin

by commonkawaiigirl



Category: Haikyuu!!
Genre: Canon Compliant, Established Relationship, Fluff and Humor, Idiots in Love, M/M, Mentions of Sex, Mentions of underage drinking, sibling dynamics
Language: English
Status: Completed
Published: 2020-07-13
Updated: 2020-07-13
Packaged: 2021-03-05 01:20:54
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,559
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25246051
Author URL: https://archiveofourown.org/users/commonkawaiigirl/pseuds/commonkawaiigirl
Summary: Being a 2nd year, and in one of the twins class, Suna felt like he was aways on babysitting duty. From walking to and from Inarizaki with them, having lunch, practicing and occasionally getting into one of their fights to separate the two when it got too physical, he almost felt like a 3rd Miya.When he managed to deal with only one of them at a time it felt like a blessing, specially if this one was Osamu.Or, alternartively: how Atsumu found out about Osamu and Suna.
Relationships: Miya Osamu/Suna Rintarou
Comments: 10
Kudos: 166





	Osamu: the cooler twin

**Author's Note:**

> Hey, so this is my first time publishing something here! English is not my native language so feel free to tell me if something isn't right.  
> This fic is basically me giving (myself) everything I want. I got into sunaosa after the week dedicated to them and I had to write something! I have some other hc's that I'm working on with more characters appearances!

Being a 2nd year, and in one of the twins class, Suna felt like he was aways on babysitting duty. From walking to and from Inarizaki with them, having lunch, practicing and occasionally getting into one of their fights to separate the two when it got too physical, he almost felt like a 3rd Miya. He, more than anyone, know the twins, really knows them. Despite their really cool and collected faces they’re really just 2 volleyball idiots, Atsumu more than Osamu obviously, but both of them were always being loud and causing trouble. 

When he managed to deal with only one of them at a time it felt like a blessing, which almost never occurred, specially if this one was Osamu. The twins were always together, they slept in bunkbeds for fucks sake. So when Atsumu went to class before them, to copy someone's homework or whatever, and left the two of them alone in the shoe locker, he saw his chance.

‘’Hey, Osamu’' 

‘’Hmm?'' Osamu looked at his secret boyfriend of 2 months, while chewing on a onigiri, his second breakfast of the day.

‘'Your parents are still out of town right?’’

‘’Ye, why?’’

‘’I think I could come over today. We could study together’' Suna smiled at him in a mischievous way, but Osamu continued to be clueless.

‘’Ye, sure. Me and 'Tsumu were plannin’ on studying math anyway, ya can join us’’

‘'I meant some studying with just the two of us’’

‘'I know Tsumu can be annoying as fuck but I think he could really use our help, ya know?

‘'You never let me forget you are a carbon copy of that nut ball, do you?’’ Osamu tilted his head, confused ‘’what I meant was we could fuck, you stupid thing’'

Osamu looked at him in shock, it was not like they never did it, Suna was just never the one to initiate it, and he never really demonstrated much desire in that particular matter. 

‘’Oh, that. Ye, that’s an awesome idea, have I mentioned how pretty you look today? Just so handsome, I could so kiss you right now’'

‘’Yeah, let’s not. So you’ll deal with Atsumu?’’

‘'Of course, anything for you, dear’' Suna was laughing at this point, Osamu never called him dear before, the prospect of sex really fried his brain, as Suna had predicted ‘’I’ll think of something to keep him out of the house for the night’’

‘'Great'' Suna lightly pulled Osamu by his belt and once his body was closer he kissed his cheek, then started to walk towards his homeroom ‘'See you later, then. I’m late for class’’ Osamu continued to look at him, dumb-folded. 

‘’Wait, Suna! We’re on the same class!’' Suna heard him screaming, he just grinned at himself.

━━━━━━━━━━━━━━

‘'Tsumu'' the other Miya called when regular practice ended and almost everyone was getting out of the gym, except the twins and Suna ‘’Ya gonna stay?’’

‘’Yeah, I wanna do some servin’ practice. Why?’’

‘'That party you were talkin' 'bout, it’s tonight right?’’

‘’Ye, shame we won’t go’’ usually Atsumu was more laid-back, maintaining his focus on volleyball and volleyball only, but a few months earlier the twins and Gin discovered a really cool bar that held really good parties once every five weeks.

‘'You should go, ‘Tsumu’'

‘'Weren't ya the one that said we needed to study for that stupid math final’' Atsumu said squeezing his eyes, suspicious of his twin brother.

‘’Ye, but I changed my mind, you deserve it really. Ya work so hard all the time, and ‘sides you’re good at math, right?’'

‘’I really deserve it don’t I?’' Atsumu said with the widest smile, changing his mind in a mere second, completely oblivious to his brother, and Suna, holding their laughter ''But what about you? Aren’t ya comin’ too?’’

‘’Nah, I’m not as good as ya in math, obviously. I’ll stay home to go over some things''  
‘'But yer staying home alone?’'

‘'I invited Suna, he needs all the help he can get in math, ya know’’ with Suna sleeping over countless times it was completely normal for him to study with them.

‘'Sunarin is really that dumb huh?

‘’Yeah, god I’m so dumb, wish I could be more like you, Atsumu’' Suna said in a monotone, Atsumu was oblivious and just laughed at him. 

‘'Not everyone can be good at everythin', like me, don’t beat yerself too much’’ Osamu could barely hold his laughter with this. 

‘'We'll go ahead home, then’' Osamu replied.

‘’Sure, sure’' and the two of them left the gym towards the locker-room to shower and head to the twins home. Once they were out of Atsumu’s sight they laughed their heads off. 

‘’Pff, how did he not notice? Atsumu is so stupid’' Suna said.

‘’Right?’' Osamu laughed. 

‘'Good for us, I guess’'

━━━━━━━━━━━━━━

‘’So, I’m leavin', losers. Have fun studyin' yer brains out, I’m gonna meet Gin there and probably be back in the mornin’’

A mere second after hearing the front door close Osamu let go of his books and was all over Suna, while the other just smiled mischievously and turned his face so Osamu’s lips would collide with his cheeks.

‘'Eager aren’t you?’' Suna said, half laughing.

‘'How could I not? I’ve been thinking 'bout it since you popped the idea. I almost had a boner in literature class’’

‘’Ew, stop. When you talk like a horny boy you remind me of Atsumu. I thought you were smoother than that’’

‘’Gross! Way to ruin my mood’' he came back to his seat, running his hands through his face, defeated ‘'You wanna drink somethin’ to set up the mood, my dearest?’’

‘'Define something’’

‘'Like one of my parents wine bottles, I heard people saying it makes them horny’’

‘'I was so gonna roast you but I admit I heard it before too’'

━━━━━━━━━━━━━━

After getting the wine and 2 glasses the two came back to the living room and started to drink while some comedy show played in the background. Osamu had his left arm around Suna while the other cuddled him. Contrary to what some might think, Suna was actually a very touchy person, with Osamu at least. In public his knee was always bumping in Osamu’s, their pinkies were sometimes intertwined and when they were alone Suna would put one of his legs on top of Osamu’s or even resort to sitting on his lap, despite being taller.

‘'Hey'' Suna called Osamu’s attention, putting both of his hands on the others cheeks, the later responded by slowly kissing the others neck.

‘'Hmm'' his boyfriend answered, already a little light headed.

‘'Do you feel guilty we haven’t told Atsumu yet?’’

‘'Just a bit, but we’ll tell him eventually, right?’' Osamu continued to kiss and lick the other’s neck and Suna moaned ‘'I love how sensitive ya are’’

‘'I'm not’’

‘’Ya totally are’’

‘’Of course I’m not’'

‘’Let’s see then’' and Osamu preceded to open the buttons in Suna's shirt, kissing the exposed skin and pulling the other in his lap for better access. He took off the shirt and moved his mouth to the Suna’s nipple, making him gasp, he proceeded to suck the first one enough so his boyfriend would moan and when he turned his attention to the second Suna was already rubbing his croach on his, looking for some friction. 

‘'This is so not fair’' Suna said with his eyes closed, between moans, Osamu suddenly stoped. 

‘'Ready to go to my room, then?’' he gave the signature Miya smile, some would say it was similar to Alice’s cheshire cat.

‘’Only if you carry me, babe’' Osamu complied and put his hands on the others ass to lift both of them up and threw him on his bunk, the bottom one, once they reached the twins room, Suna retaliated by pulling Osamu towards him by the school tie he was still wearing and they resumed into their kissing. 

━━━━━━━━━━━━━━

Being with Suna was always nice, it was like a little thing he could have all to himself, not having to share even a little with his brother. Suna was in love with him, only him, and damn that felt good. Hiding their relationship wasn’t the best but these moments always made up for it, the light touches and stolen kisses they shared at school or at home when Atsumu wasn’t looking could never compare to now, being glued to each other, despite both not being big fans of physical contact, in the privacy of Osamu’s house was just perfect. They were only dating for 3 months, but Osamu liked to think it was love at first sight. Meeting Suna in the classroom and later finding out he was also in the volleyball club was nice and getting to know Suna was even better. Knowing about his love for ice pops, seeing him interact with his father and mother, and how much he took after them, hearing about his life in Tokyo and the friends he still had there. Every little thing about Suna felt precious to him.

He was sure that having sex with Suna was the best thing he could ever experience in his lifetime. Despite both of them being inexperienced, every touch, every kiss felt just right and left them needing more. Their bodies were so close but they wanted to get closer. And that’s how they found each other in the aftermath, both out of breath and Suna still under Osamu, caressing his cheek and smiling at him. They could spend hours like this, just looking at each other. 

‘’You're so pretty Rin’’

‘’Right back at you’' Suna smiled lovingly and pulled his boyfriend’s face closer and lazily kissed him ‘’So.. hmm I could probably go again in a few minutes, you up for it?’'

‘'Hm ye? Who do you think I am, an old man? Seeing you like this is making me get hard again’' Osamu grinned ''Never thought you’d be this horny thought, not that I’m complaining, but what got you like that out of the blue?’’

‘'You know on Wednesday when Atsumu wanted to fight and you totally manhandled him and thew him in the ball cart?’' Osamu nodded ‘’yeah, there. The extra kilogram you have on Atsumu totally makes the difference, I think it’s all in your ass’' he squeezed his ass with both hands.

‘'So you only want me for my ass huh?’' Osamu said laughing, still a little intoxicated from the wine they drank earlier ‘’Pervert''

‘’I'll have you know that I’m not in this only for your ass’' Suna smiled mischievously and pushed Osamu down, staying on top of him ‘'it's also your pretty dick, you know''

━━━━━━━━━━━━━━

‘'Stupid party with stupid people, why did I went anyway?’' Atsumu entered the Miya household at 1a.m. after spending only 3 hours on his so called ‘awesome party’. He expected to get home to a silent house since Osamu always slept early, but he heard some noises upstair so he assumed his brother was still awake.

‘’Samu? That party totally sucked man. Should’ve stayed home with ya guys’’ he opened the door to their shared room, hoping to find Osamu still studying or having a late night snack, what he never imagined to find was his twin brother balls deep into their teammate and said teammate ridiculously white ass ‘'Oh my god OH MY GOD? MY EYES’' he screamed, which seemed to get the other two attention, Suna quickly got off of Osamu and snatched the bedsheet to cover himself. Atsumu left the room, still screaming and the couple looked at one another astonished.

‘'Now we can skip the telling Atsumu part’' Suna was the first one to speak and Osamu even laughed a little at his logic.

‘'I'll go talk to him’' Osamu got out of the bed and started to walk towards the door but Suna held his arm ‘'Sorry Rin, we can finish this some other time’’

‘'I was going to tell you to put on some pants first, but it’s your choice’'

‘'Hm ye, great idea’' Osamu picked up some track pants and finally left the room, Suna rolled his eyes and started to look for some clothes to also put on and check on the twins.

‘’Don’t sit next to me with a boner, yer so gross’' Atsumu yelled as soon as Osamu reached the living room, he then sat in the couch in the opposite side of his brother.

‘'You scared it away with yer screaming, ya idiot’'

‘'The fuck 'Samu? Since when is this a thing?’’

‘’Wait, you’re actually mad?’' Atsumu didn’t answer, just turned his face, like a kid does when gets mad at his parents ‘'You're mad because I didn’t told you? I’m sorry, it’s just that we didn’t want the team finding out for now, and you do have a big mouth ‘Tsumu''

‘'It's not that’’

‘'Is it because I tricked you into thinking you were too smart to study math?’’

‘'You did that? Samu, yer seriously the worst’' 

‘’Is it the gay thing then?’’ at this prospect Osamu became apprehensive, the thought of Atsumu, his twin brother, the person he trusted (and liked, despite all the bickering) in the world not accepting him was terrifying

‘'The hell? 'Course it’s not that! You know I’d bang some guys in a heartbeat’’

‘'What is it then? 

‘’It's just that, when did you became so cool?’' Atsumu said, half crying ‘’having a secret relationship and then having sex before me? That’s so not fair’’

‘'You're mad because of this?’’ Suna came forward from his place behind the wall to sit next to Osamu, once he understood that there really wasn’t going to have a serious fight between the twins. Suna was wearing one of Osamu’s shirts and boxers witch Atsumu whispered ew and Suna promptly replied that they saw each other naked all the time in the locker room ‘’when I thought you couldn’t get more annoying…’'

‘'I have so much more fangirls than ‘Samu? This isn’t right ya know’’

‘'You're so simple minded’' Suna rolled his eyes ''So, the guys you mentioned you would totally bang, who are they? Tell your dear brother-in-law’’

‘'Like hell I’m telling you, ya ugly twin fucker’’

‘'You're ugly’’

‘’Well yer datin’ my face so ya can’t really be serious’’

‘’am not! Osamu is so much prettier than you and hotter, I bet his dick is prettier too’’

‘’I can state for a fact that we have the exact same dick. Can’t say the same ‘bout yer ugly white ass’’

‘'I'm going to kill you’' Suna got up to hit Atsumu, but Osamu was faster and held him by the waist 

‘'For someone that swears he won’t get caught up in our dumb antics you sure seem pretty invested in Atsumu’s shit’’

‘’It's you fault though, you’re totally rubbing off on me’’ he rolled his eyes. Osamu smiled lovingly at his not-so-secret-boyfriend, and kissed his lips, forgetting for a minute that his twin brother was sitting just next to him.

‘’Ya two are so fuckin’ gross. I’m goin’ to bed, had enough for today’’

‘’Wait, we’ll go too’' Suna got off his lap and held his hand out for him to take.

‘'If I hear a single noise I’m going to end you, I’m not even joking’’

‘'We'll fuck quietly then’’

‘’OSAMU''

**Author's Note:**

> Hit me up on my (new) twitter account @commonkawaigirl if you're also sunaosa obsessed.


End file.
